U.S. patent number 8,875,697 [Application Number 12/176,582] was granted by the patent office on 2014-11-04 for drug delivery apparatus and method.
This patent grant is currently assigned to RIC Investments, LLC. The grantee listed for this patent is Jonathan S. H. Denyer, Ivan R. Prince, Ian Rabbetts. Invention is credited to Jonathan S. H. Denyer, Ivan R. Prince, Ian Rabbetts.
United States Patent |
8,875,697 |
Denyer , et al. |
November 4, 2014 |
Drug delivery apparatus and method
Abstract
A drug delivery apparatus includes a mouthpiece portion having
an internal conduit for delivering an aerosol including the drug to
the patient. The internal conduit has an inlet end and a mouthpiece
end that is structured to be received in the patient's mouth. The
mouthpiece portion is structured to operate at a substantially
fixed inhalation flow rate when the patient inhales through the
mouthpiece end. The apparatus further includes an aerosol generator
for generating the aerosol from a drug supply and injecting the
aerosol into a first region within the mouthpiece portion located
between an outlet of the aerosol generator and the inlet end of the
conduit. The mouthpiece portion also includes a flow accelerating
mechanism that causes a localized flow rate at the first region to
be greater than the inhalation flow rate. A method is also provided
that increases the local flow rate within the mouthpiece
portion.
Inventors: |
Denyer; Jonathan S. H.
(Chichester, GB), Prince; Ivan R. (Chichester,
GB), Rabbetts; Ian (Hayling Island, GB) |
Applicant: |
Name |
City |
State |
Country |
Type |
Denyer; Jonathan S. H.
Prince; Ivan R.
Rabbetts; Ian |
Chichester
Chichester
Hayling Island |
N/A
N/A
N/A |
GB
GB
GB |
|
|
Assignee: |
RIC Investments, LLC
(Wilmington, DE)
|
Family
ID: |
39739802 |
Appl.
No.: |
12/176,582 |
Filed: |
July 21, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20090025714 A1 |
Jan 29, 2009 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60961718 |
Jul 24, 2007 |
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Current U.S.
Class: |
128/200.16;
128/203.15; 128/200.23 |
Current CPC
Class: |
A61M
15/002 (20140204); A61M 15/0021 (20140204); A61M
15/00 (20130101); A61M 2016/0036 (20130101); A61M
2202/04 (20130101); A61M 15/0085 (20130101); A61M
2205/502 (20130101) |
Current International
Class: |
A61M
11/00 (20060101); B05B 17/06 (20060101); B05D
7/14 (20060101); A61M 16/00 (20060101); B65D
83/06 (20060101); A61M 15/00 (20060101) |
Field of
Search: |
;128/203.12,203.15,203.21,203.23,203.24,204.18,204.21,204.23,204.25-204.28,205.23,200.11-200.24,200.26,205.24-205.25,206.29,207.12,207.14,207.16
;604/68-72 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2395437 |
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May 2004 |
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GB |
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WO 2004041336 |
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May 2004 |
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WO |
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WO 2006013952 |
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Feb 2006 |
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WO |
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Other References
International Preliminary Report on Patentability for
PCT/GB2008/002538. cited by examiner.
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Primary Examiner: Ho; (Jackie) Tan-Uyen T
Assistant Examiner: Han; Mark K
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. .sctn.119(e) from
provisional U.S. patent application No. 60/961,718 filed Jul. 24,
2007, the entire contents of which are incorporated herein by
reference.
Claims
What is claimed is:
1. A drug delivery apparatus for delivering an aerosol including a
drug to a patient while reducing deposition of the aerosol on the
apparatus, comprising: a mouthpiece portion including: a chamber
having an air inlet, an internal conduit for delivering the aerosol
to the patient, the internal conduit having a conduit inlet and a
mouthpiece opposite the conduit inlet, wherein the mouthpiece is
structured to be received in the mouth of the patient, the
mouthpiece portion being further structured such that the patient
inhales breathable gas via the air inlet of the chamber into the
conduit inlet of the internal conduit and through the mouthpiece of
the internal conduit, and a flow accelerator disposed within the
internal conduit near the conduit inlet, wherein the flow
accelerator is a removable insert inserted within the internal
conduit, the insert having an orifice; and an aerosol generator
configured to generate the aerosol from a supply of the drug and
further configured and arranged to inject the aerosol into the
conduit inlet of the internal conduit of the mouthpiece portion,
wherein said flow accelerator is structured to increase velocity of
a combined flow of substantially all the breathable gas from the
air inlet and substantially all the aerosol from the aerosol
generator within the internal conduit.
2. The drug delivery apparatus according to claim 1, wherein the
insert includes: a body structured to be received within the
internal conduit near the conduit inlet, an outer lip extending
around an outer periphery of the body, and one or more flanges
extending from the outer lip, wherein the one or more flanges are
structured to fit over an outside of the conduit inlet to hold the
insert in place.
3. The drug delivery apparatus according to claim 1, wherein the
conduit inlet is generally circular and has across sectional
diameter, and wherein the orifice of the insert is generally
circular and has an orifice diameter, wherein the orifice diameter
is smaller than the cross sectional diameter of the conduit
inlet.
4. The drug delivery apparatus according to claim 1, wherein the
conduit inlet is generally circular and has a cross sectional
diameter, and wherein a cross-section of the orifice is defined by
a first arcuate edge located opposite a second arcuate edge,
wherein a degree of curvature of the first arcuate edge is greater
than a degree of curvature of the second arcuate edge.
5. The drug delivery apparatus according to claim 4, wherein the
insert has a periphery, wherein the second arcuate edge is located
closer to the periphery of the insert than said first arcuate edge,
and wherein the first arcuate edge is located closer to a center of
the insert than the second arcuate edge.
6. The drug delivery apparatus according to claim 5, further
comprising a control valve disposed within the mouthpiece portion,
wherein the control valve is configured to control inhalation flow,
wherein operation of the control valve causes the flow within the
internal conduit to be uneven, and wherein orientation and shape of
the orifice of the insert are arranged and structured to compensate
for unevenness of the flow within the internal conduit.
7. The drug delivery apparatus according to claim 1, wherein the
orifice is asymmetrical relative to a center of the insert.
8. The drug delivery apparatus according to claim 1, wherein the
flow accelerator is formed integrally as part of the internal
conduit.
9. The drug delivery apparatus according to claim 8, wherein the
flow accelerator is formed near the conduit inlet.
10. The drug delivery apparatus according to claim 1, wherein
increasing the velocity of the combined flow causes a reduction in
particle size of the aerosol.
11. The drug delivery apparatus according to claim 1, wherein the
aerosol generator includes a mesh plate having a plurality of
holes, a horn, and a piezoelectric transducer operatively coupled
to the horn for causing the horn to vibrate, wherein vibration of
the horn forces the drug through the holes of the mesh plate to
form the aerosol.
12. The drug delivery apparatus according to claim 1, wherein the
internal conduit is generally cylindrically shaped, and wherein the
insert is generally cylindrically shaped and includes a body
structured to be received within the internal conduit near the
conduit inlet.
13. The drug delivery apparatus according to claim 1, wherein the
flow accelerator causes the velocity of the combined flow through
the insert to be in the range of approximately 100 cm/sec to
approximately 500 cm/sec.
14. A drug delivery apparatus for delivering an aerosol including a
drug to a patient while reducing deposition of the aerosol on the
apparatus, comprising: a mouthpiece portion including: a chamber
having an air inlet, an internal conduit for delivering the aerosol
to the patient, the internal conduit having a conduit inlet and a
mouthpiece opposite the conduit inlet, and a flow accelerator
disposed within the internal conduit near the conduit inlet,
wherein the flow accelerator is an insert inserted within and
removable from the internal conduit, the insert having an orifice,
wherein the internal conduit is generally cylindrically shaped,
wherein the insert is generally cylindrically shaped and includes:
a body structured to be received within the internal conduit near
the conduit inlet, an outer lip extending around an outer periphery
of the body, and one or more flanges extending from the outer lip,
wherein the outer lip is structured to rest on top of the conduit
inlet and wherein the one or more flanges are structured to fit
over an outside of the conduit inlet to hold the insert in place,
wherein the mouthpiece is structured to be received in the mouth of
the patient, the mouthpiece portion being further structured such
that the patient inhales breathable gas via the air inlet of the
chamber into the conduit inlet of the internal conduit and through
the mouthpiece of the internal conduit; and an aerosol generator
configured to generate the aerosol from a supply of the drug and
further configured and arranged to inject the aerosol into the
conduit inlet of the internal conduit of the mouthpiece portion,
wherein the flow accelerator is structured to increase velocity of
a combined flow of substantially all the breathable gas from the
air inlet and substantially all the aerosol from the aerosol
generator within the internal conduit.
15. A method of delivering an aerosol including a drug to a patient
via a drug delivery apparatus while reducing deposition of the
aerosol on the apparatus, the method comprising: providing a
mouthpiece portion including a chamber having an air inlet and an
internal conduit, the internal conduit having a conduit inlet, the
internal conduit for delivering breathable gas from the air inlet
combined with the aerosol through the conduit inlet to the patient,
the internal conduit further having a mouthpiece opposite the
conduit inlet that is structured to be received in the mouth of the
patient, the mouthpiece portion being structured such that the
patient inhales through the mouthpiece; generating the aerosol from
a supply of the drug; injecting the aerosol into the conduit inlet
of the internal conduit; and increasing velocity of a combined flow
of substantially all the breathable gas from the air inlet of the
chamber and substantially all the aerosol within the internal
conduit through a removable insert inserted within the internal
conduit and removable from the internal conduit.
16. A method of delivering an aerosol including a drug to a patient
via a drug delivery apparatus while reducing deposition of the
aerosol on the apparatus, the method comprising: providing a
mouthpiece portion including a chamber having an air inlet and an
internal conduit, the internal conduit having a conduit inlet, the
internal conduit for delivering breathable gas from the air inlet
combined with the aerosol through the conduit inlet to the patient,
the internal conduit further having a mouthpiece opposite the
conduit inlet that is structured to be received in the mouth of the
patient, the mouthpiece portion being structured such that the
patient inhales through the mouthpiece; detecting the commencement
of inhalation by the patient through the mouthpiece; generating the
aerosol from a supply of the drug; injecting the aerosol into the
conduit inlet of the internal conduit for at least a portion of the
time that the patient is inhaling through the mouthpiece;
increasing velocity of a combined flow of substantially all the
breathable gas from the air inlet of the chamber and substantially
all the aerosol within the internal conduit through a removable
insert inserted within the internal conduit and removable from the
internal conduit; signaling the patient to cease inhalation through
the mouthpiece after a pre-set period of time has elapsed from the
detection of the commencement of inhalation; and adjusting the
pre-set period of time for subsequent inhalations through the
mouthpiece based upon a time difference between a time that the
signaling step is commenced and a time at which the patient
actually ceases inhalation through the mouthpiece.
Description
FIELD OF THE INVENTION
The present invention relates to devices that deliver drugs to a
patient in aerosol form, commonly referred to as nebulizers, and in
particular to a drug delivery apparatus and method that improves
performance by reducing the particle size of the drug included in
the aerosol.
BACKGROUND OF THE INVENTION
A number of devices are available for delivering a drug into the
lungs of a patient. Once such device is a nebulizer, which is a
device that is used for converting a liquid, such as a liquid
medication, into an aerosol which is then inhaled by the patient,
typically through a mouthpiece. A number of different types of
nebulizers exist, such as, without limitation, jet nebulizers and
ultrasonic nebulizers. A typical jet nebulizer uses compressed air
to generate the aerosol from the liquid. One type of ultrasonic
nebulizer employs acoustic waves having an ultrasonic frequency
that are directed to a point on the surface of the liquid that is
to be converted into an aerosol. At the point on the surface of the
liquid where these ultrasonic waves converge, they will produce
capillary waves that oscillate at the frequency of the ultrasonic
waves. If the amplitude of the waves is large enough, the peaks of
the capillary waves will break away from the liquid and be ejected
from the surface of the liquid in the form of droplets, thereby
forming the aerosol. A device that is often used for generating
ultrasonic waves in an ultrasonic nebulizer is a piezoelectric
transducer (such as a piezoelectric crystal), which vibrates and
generates ultrasonic waves in response to an applied electric
field. In another type of ultrasonic nebulizer, the liquid that is
to be converted into an aerosol is forced through a mesh (thereby
creating liquid droplets) by the vibration of a piezoelectric
crystal acting upon a horn. In this type of ultrasonic nebulizer,
the gauge of the mesh determines the size of the droplets which are
created to form the aerosol.
Conventional nebulizer systems provide a continuous aerosol/drug
output, and thus the amount of drug inhaled is dependent upon the
patient's breathing pattern. The duty cycle of the patient's
breathing pattern is typically 40:60. This means that the patient
spends 40 percent of a single respiratory cycle in inspiration and
60 percent of the time in expiration. Thus, 60 percent of the drug
delivered from the nebulizer will be wasted to the environment
during expiration. In addition, the breathing pattern of a single
patient over the course of a treatment will vary. In order to
address these issues, more sophisticated nebulizer systems have
been developed which adapt the delivery of aerosol to the patient's
breathing pattern, delivering medication only when the patient is
inhaling through the mouthpiece.
Adaptive nebulizer systems as just described have been developed
which are capable of a number of different modes of operation. For
example, one such system is capable of operating in either a tidal
breathing mode and a target inhalation mode.
In the tidal breathing mode (TBM), the nebulizer system monitors
the flow and inhalation time for the first few breaths (.e.g.,
three breaths) of each treatment. This information is used to
predict how long the next breath is going to be. Once this has been
calculated, aerosol is emitted into the beginning of the next
inhalation. The prediction is updated after each new breath to
ensure accuracy through the whole of the treatment. In a typical
implementation, the device will emit aerosol into approximately 50
to 80 percent of each inhalation. In this mode, very little of the
medication is wasted to atmosphere because the aerosol is emitted
only when the patient is breathing in.
In the target inhalation mode (TIM), the nebulizer system
encourages each patient to inhale for as long as they can, as this
can result in a greater amount of the medication getting into the
lungs, and can also reduce the treatment time. In particular, the
patient is instructed to breathe in through the mouthpiece until a
signal, such as vibration through the mouthpiece, is provided. The
time between the start of the breath and the signal is called the
target inhalation time--in other words, how long the patient should
inhale. At the beginning of the first treatment, the target
inhalation time is set to predetermined time, such as three
seconds. If the patient is able to inhale past the target
inhalation time, then the target inhalation time for the next
breath is made a little longer. In this way, the duration of the
breath is gradually increased until the patient reaches a target
inhalation time that is suited to his/her own capabilities. If the
patient is not able to inhale past the target inhalation time, then
the target inhalation time for the next breath is made a little
shorter. Also, there is always a gap, such as a two second gap,
between the end of aerosol production and the target inhalation
time signal to ensure that substantially all of the aerosol reaches
the patient's lungs. One particular implementation of a nebulizer
system which is able to operate in a target inhalation mode is
described in United States Patent Application Publication No.
2006/0243277, entitled "Inhalation Method and Apparatus" and
assigned to the assignee hereof, the disclosure of which is
incorporated herein by reference.
Furthermore, the target inhalation mode is typically operated at a
fixed inhalation flow rate, e.g., 15 l/min, which is lower than the
inhalation flow rate of the tidal breathing mode, which can be as
high as 80 l/min. It has been discovered that this difference in
flow rates, particularly in the locality where the aerosol plume is
generated, results in the aerosol particle size in the target
inhalation mode being larger than the aerosol particle size in the
tidal breathing mode. As will be appreciated by those of skill in
the art, the smaller the particle size of the aerosol, the greater
the lung deposition of the medication, as less medication will get
trapped in the patient's upper airway and more medication will
reach the periphery of the patient's lungs. Thus, it would be
advantageous to be able to reduce the particle size of the aerosol
that is generated by a nebulizer system that is operating at a
given, fixed inhalation flow rate, such as a nebulizer system that
is operating in the target inhalation mode at a 15 l/min inhalation
flow rate, and, as a result, enhance lung deposition.
SUMMARY OF THE INVENTION
In one embodiment, the present invention provides a drug delivery
apparatus for delivering an aerosol including a drug to a patient.
The apparatus includes a mouthpiece portion having an internal
conduit for delivering the aerosol to the patient (by inhalation
through the internal conduit). The internal conduit has an inlet
end and a mouthpiece end opposite the inlet end that is structured
to be received in the mouth of the patient. The mouthpiece portion
is structured to operate at a substantially fixed inhalation flow
rate, such as through a control valve provided in the mouthpiece
portion, when the patient inhales through the mouthpiece end. The
apparatus further includes an aerosol generator for generating the
aerosol from a supply of the drug and injecting the aerosol into a
first region within the mouthpiece portion located between an
outlet of the aerosol generator and the inlet end of the internal
conduit. In addition, the mouthpiece portion includes a flow
accelerating mechanism that causes a localized flow rate at the
first region to be greater than the inhalation flow rate.
The flow accelerating mechanism may take on a number of different
forms. For example, and without limitation, the flow accelerating
mechanism may be an insert having an orifice that is inserted
within the internal conduit at the inlet end. In one particular
embodiment, the internal conduit is generally cylindrically shaped
and has a cross sectional diameter, and the orifice is generally
circular and has an orifice diameter, wherein the orifice diameter
is smaller than the cross sectional diameter. In another particular
embodiment, the internal conduit is generally cylindrically shaped
and has a cross sectional diameter, and the orifice is defined by a
first arcuate edge located opposite a second arcuate edge, wherein
a degree of curvature of the first arcuate edge is greater than a
degree of curvature of the second arcuate edge. Preferably, the
second arcuate edge is located closer to an outer edge of a top
surface of the insert than the first arcuate edge, and the first
arcuate edge is located closer to a center of the insert than the
second arcuate edge. In another embodiment, the flow accelerating
mechanism is formed integrally as part of the internal conduit. In
this embodiment, the flow accelerating mechanism may be an end
portion of the internal conduit at the inlet end, wherein the end
portion has an orifice formed therein. Alternatively, the internal
conduit may be generally cone shaped and taper outwardly from the
inlet end.
In another embodiment, the present invention provides a method of
delivering an aerosol including a drug to a patient that includes
providing a mouthpiece portion including an internal conduit for
delivering said aerosol to said patient, wherein the internal
conduit has an inlet end and a mouthpiece end opposite the inlet
end that is structured to be received in the mouth of the patient.
The mouthpiece portion is structured to operate at an inhalation
flow rate when the patient inhales through the mouthpiece end. The
method further includes generating the aerosol from a supply of the
drug and injecting the aerosol into a first region within the
mouthpiece portion located between a location at which said aerosol
is generated and the inlet end of the internal conduit, and causing
a localized flow rate within the mouthpiece portion at the first
region to be greater than the inhalation flow rate.
In still another embodiment, the present invention provides a
method of delivering an aerosol including a drug to a patient
including providing a mouthpiece portion including an internal
conduit for delivering the aerosol to the patient, wherein the
internal conduit has an inlet end and a mouthpiece end opposite the
inlet end that is structured to be received in the mouth of the
patient. The mouthpiece portion is structured to operate at an
inhalation flow rate when the patient inhales through the
mouthpiece end. The method further includes detecting the
commencement of inhalation by the patient through the mouthpiece
end, generating the aerosol from a supply of the drug and injecting
the aerosol into a first region within the mouthpiece portion
located between a location at which the aerosol is generated and
the inlet end of the internal conduit for at least a portion of the
time that the patient in inhaling through the mouthpiece end, and
causing a localized flow rate within the mouthpiece portion at the
first region to be greater than the inhalation flow rate during the
generating step. Finally, the method includes signaling the patient
to cease inhalation through the mouthpiece end after a pre-set
period of time has elapsed from the detection of the commencement
of inhalation, and adjusting the pre-set period of time for
subsequent inhalations through the mouthpiece end based upon a time
difference (positive or negative) between a time that the signaling
step is commenced and a time at which the patient actually ceases
inhalation through the mouthpiece end.
Therefore, it should now be apparent that the invention
substantially achieves all the above aspects and advantages.
Additional aspects and advantages of the invention will be set
forth in the description that follows, and in part will be obvious
from the description, or may be learned by practice of the
invention. Moreover, the aspects and advantages of the invention
may be realized and obtained by means of the instrumentalities and
combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate presently preferred
embodiments of the invention, and together with the general
description given above and the detailed description given below,
serve to explain the principles of the invention. As shown
throughout the drawings, like reference numerals designate like or
corresponding parts.
FIG. 1 is a front elevational view and FIG. 2 is a left side
elevational view of a nebulizer device according to one embodiment
of the invention;
FIG. 3 is a schematic diagram of the nebulizer device of FIGS. 1
and 2;
FIG. 4A is a side elevational view and FIG. 4B is a top plan view
of an insert forming a flow accelerating mechanism according to one
embodiment of the present invention;
FIG. 5 is an end view of a mouthpiece portion forming a part of the
nebulizer device shown in FIGS. 1 and 2 which includes the insert
according to an aspect of the invention;
FIG. 6 is a schematic diagram of an alternative embodiment of a
mouthpiece portion that may be used in the nebulizer device shown
in FIGS. 1 and 2;
FIG. 7 is a side elevational view of an insert forming a flow
accelerating mechanism according to another embodiment of the
present invention;
FIG. 8 is a top plan view of an insert forming a flow accelerating
mechanism according to still another embodiment of the present
invention;
FIG. 9 is a schematic diagram of a further alternative embodiment
of a mouthpiece portion that may be used in the nebulizer device
shown in FIGS. 1 and 2;
FIG. 10A is a schematic diagram which illustrates aerosol flow in
one embodiment of an internal conduit of a mouthpiece portion that
may be used in the nebulizer device shown in FIGS. 1 and 2; and
FIG. 10B is a schematic diagram which illustrates aerosol flow in
another embodiment of an internal conduit of a mouthpiece portion
that may be used in the nebulizer device shown in FIGS. 1 and
2.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
FIG. 1 is a front elevational view and FIG. 2 is a left side
elevational view of a nebulizer device 5 according to one
embodiment of the invention. FIG. 3 is a schematic diagram of the
nebulizer device 5 which shows selected components thereof in a
simplified or symbolic form. The nebulizer device 5 functions as a
drug delivery system for delivering a drug in the form of an
aerosol into the lungs of a patient. The nebulizer device 5
includes a main housing 10 which houses certain components (shown
in FIG. 3 and described below) of the nebulizer device 5 and a
mouthpiece portion 15 which is removeably attached to the main
housing 10. Of course, the nebulizer device could have a variety of
other outputs other than a mouthpiece. For instance, the device may
be connected to an endotracheal tube, a mask, or a respiratory
support device. As shown schematically in FIG. 3, the mouthpiece
portion 15 includes a chamber 20 which, when the mouthpiece portion
15 is attached to the main housing 10, is structured to receive the
aerosol that is generated by the components in the main housing 10
as described in more detail below. The chamber 20 includes an air
inlet 25 and an internal conduit 30 having an inlet end 35 and a
mouthpiece end 40 that is structured to be received in the mouth of
the patient. As shown by the arrows in FIG. 3, when the patient
places his or her mouth on the mouthpiece end 40 and inhales, air
is caused to flow into the chamber 20 from the air inlet 25 and
through the internal conduit 30 from the inlet end 35 to the
mouthpiece end 40. As will be appreciated, that air stream carries
the aerosol that is generated in the manner described below into
the lungs of the patient.
As seen in FIG. 3, the main housing 10 includes a mesh plate 45
(including a plurality of miniature holes therein), a reservoir 50
for holding the liquid (drug) to be converted into an aerosol a
horn 55, and a piezoelectric transducer 60 operatively coupled to
the horn 55. The main housing 10 also includes a controller 65,
which may be a microprocessor, microcontroller, or some other
suitable electronic control device or circuitry, and a power supply
70, which preferably is a rechargeable battery. The horn 55 is
located close to the rear face of the mesh plate 45 and may be
caused to vibrate by the piezoelectric transducer 60 under the
control of the controller 65, with the power to drive the
piezoelectric transducer 60 being provided by the power supply 70.
The liquid in the reservoir 50 is in fluid contact with the rear
face of the mesh plate 45. When the piezoelectric transducer 60 is
caused to vibrate, it drives the horn 55 to vibrate in the region
of the mesh plate 45. As a result of such vibration of the horn 55,
the liquid from the reservoir 50 is forced through the holes of the
mesh plate 45, thereby generating an aerosol plume 75 that is
injected into the chamber 20 and ultimately into the internal
conduit 30. As seen in FIG. 1, the main housing 10 includes an LCD
12 for providing information to the patient about the treatment and
operation of the nebulizer device 5, and button 14 for providing
input for controlling various aspects of the nebulizer device
5.
According to one aspect of an embodiment of the invention, the
internal conduit is provided with a flow accelerating mechanism 80
at the inlet end 35 of the internal conduit 30. The flow
accelerating mechanism 80 functions to cause the local flow rate in
the region 85 where the aerosol plume 75 is injected into the
chamber 20 to be increased (relative to the inhalation flow rate at
which the mouthpiece portion 15 is structured to operate). For
example, if the nebulizer device 5 were operating in a mode (e.g.,
a TIM mode, TBM mode) which employs a fixed inhalation flow rate
through the mouthpiece portion 15, such as in the range of 10-25
l/min, the flow accelerating mechanism 80 would cause the local
flow rate in the region 85 to be higher than 15 l/min, such as in
the range of 100-500 cm/sec (the actual flow rate will depend on
the structure of the flow accelerating mechanism 80). The increased
flow rate in the region 85 promotes more effective mixing of the
inhalation flow and the aerosol particles, thereby reducing the
particle size of the aerosol. As described elsewhere herein,
reducing the particle size of the aerosol is advantageous as it
enhances lung deposition of the medication.
In one particular embodiment, the flow accelerating mechanism 80 is
an insert 80A as shown FIGS. 4A and 4B (and in FIG. 3) which is
adapted to be inserted and held within the inlet end 35 of the
internal conduit 30 of the mouthpiece portion 15. Of course, the
flow accelerating mechanism 80 may have a variety of other
configurations. For instance, the flow accelerating mechanism 80
may be formed integrally with the inlet end 35. Alternatively, the
flow accelerating mechanism may be formed as a cap fitted over the
inlet end, or even configured as a cartridge slid into place
through an opening in one side of the inlet end 35. As seen in
FIGS. 4A and 4B, the insert 80A has a generally cylindrical shape
including a body 90 adapted to be received within the inlet end 35
and a top surface 95. In addition, the insert 80A includes an
orifice 100 having a circular shape. It is the orifice 100 that
causes the flow rate in the region 85 where the aerosol plume 75 is
injected into the chamber 20 to be increased relative to the
inhalation flow rate in the rest of the chamber 20. The insert 80A
also includes an outer lip 105 extending around the outer periphery
of the body 90 and a pair of flanges 110 extending from the outer
periphery of the body 90. The outer lip 105 is structured to rest
on top of and the flanges 110 are structured to fit over the
outside of the inlet end 35 to hold the insert 80A in place.
As will be appreciated, the insert 80A shown in FIGS. 4A and 4B
assumes that the outer edge of the inlet end 35 of the internal
conduit 30 lies in a plane that is perpendicular to the
longitudinal axis of the internal conduit 30 as is shown in FIG. 3.
However, that may not always be the case. For example, the outer
edge of the inlet end 35 may lie in a plane that is oriented at an
angle that is less than 90 degrees with respect to the longitudinal
axis of the internal conduit 30 as shown in mouthpiece portion 15'
shown FIG. 6. The outer edge of the inlet end 35 may be provided in
that manner to, for example, compensate for an uneven flow within
the chamber 20 caused by a valve 115 for controlling inhalation
flow rate that is offset within the chamber 20 (as shown in FIG.
5). In such a case, the flow accelerating mechanism 80 will
preferably be in the form of an insert 80B shown in FIG. 7. As seen
in FIG. 7, the outer lip 105 is oriented at an angle with respect
to the top surface 95. That angle will compensate for the outer
edge of the inlet end 35 so that the top surface 95 will be
generally perpendicular to the longitudinal axis of the internal
conduit 30 when the insert 80B is inserted within the inlet end 35
of the internal conduit 30.
In addition, in situations where there is an uneven flow within the
chamber 20 caused by, for example, a valve 115 for controlling
inhalation flow rate that is offset within the chamber 20 (as shown
in FIG. 5), it has been found that if an insert such as 80A or 80B
is employed, there is a tendency for the medication in the aerosol
to become deposited at a particular location on the insert 80A or
80B. Specifically, it has been found that medication tends to
become deposited on the lower right hand quadrant of the insert 80A
or SOB (in the orientation of FIG. 5) when the valve 115 is located
in the position shown in FIG. 5. Thus, in order to compensate for
this phenomenon, an insert 80C according to an alternate embodiment
of the invention as shown in FIG. 8 may be employed. The insert 80C
includes an orifice 120 that, instead of being circular in shape,
has the shape shown in FIG. 8. In particular, the orifice 120 has
an enlarged portion 125 that located in the area where medication
would normally tend top become deposited in order to allow that
medication to instead pass through to the internal conduit 30. The
orifice 120 is defined by a first arcuate edge 130 located opposite
a second arcuate edge 135 wherein the degree of curvature of the
first arcuate edge 130 is greater than the degree of curvature of
the second arcuate edge 135. In addition, as seen in FIG. 8, in the
preferred embodiment, the second arcuate edge 135 is located closer
to the outer edge of the top surface 95 than the first arcuate edge
130, which tends to be located closer to the center of the insert
80C.
In an alternative embodiment, rather than the flow accelerating
mechanism 80 being in the form of a separate insert 80A, 80B, or
80C as just described, it may be formed integrally with the
internal conduit 30 as shown in FIG. 9 in the form of an orifice
140 provided in the inlet end 35 of the internal conduit 30. In
this embodiment the orifice 140 preferably has a maximum width
(e.g., diameter in the case of a circular orifice 140) that is less
than the diameter of the cylindrically shaped internal conduit
30.
Moreover, when the internal conduit 30 of the mouthpiece portion 15
is shaped as shown in FIGS. 3, 6 and 9 (i.e., generally
cylindrical), the vortex spread from the orifice 100 of the insert
80A or 80B or the orifice 120 of the insert 80C may tend to cause
medication to be deposited on the inside of the internal conduit
30. This tendency is illustrated schematically in FIG. 10A. FIG.
10B shown an internal conduit 30' according to an alternative
embodiment that may form part of the mouthpiece portion 15. As seen
in FIG. 10B, the internal conduit 30' is tapered outwardly,
preferably in the form of a cone, beginning at the inlet end 35. In
this embodiment, like the embodiment shown in FIG. 9, the flow
accelerating mechanism 80 is preferably formed integrally with the
internal conduit 30' in the form of a circular orifice 145 provided
in the inlet end 35 of the internal conduit 30' (it will be
understood that alternatively an insert as described elsewhere
herein may also be used). The orifice 145 thus has a diameter that
is equal to the smallest diameter of the cross-section of the
tapered, preferably cone shaped internal conduit 30'. The tapered,
preferably cone shaped internal conduit 30' reduces turbulence just
inside the inlet end 35 and as a result reduces deposition of
medication on the inside of the internal conduit 30'.
In operation, the present invention also provides a method of
delivering aerosol to a patient. Specifically, the aforementioned
device may be utilized by coupling the device to the airway of the
patient such as by placing a mouthpiece into the patient's mouth, a
mask over the patient's mouth and/or nose, connecting the device to
an endotracheal tube, or connecting the device to a respiratory
circuit. In one embodiment, the outlet end is a mouthpiece
configured to be received in the mouth of the user. The mouthpiece
is sized and configured to achieve a desirable flow rate as the
patient inhales. Aerosol is generated from a supply of drug and
injected into a first region of the mouthpiece. The airflow is
accelerated through a localized region of the mouthpiece. In one
embodiment, the aerosol generation is initiated in response to a
sensor (e.g. flow rate sensor) detecting the breathing pattern
including inhalation and exhalation. The nebulizer device includes
a processor and a memory which stores a pre-set inhalation time
goal. Once the patient has reached the pre-set inhalation time, a
signal may be provided to the patient indicating that the patient
should cease inhalation. As the patient utilizes the device, the
patient's performance may be monitored by the processor, and the
processor may adjust the pre-set inhalation time period based upon
the detected patient performance. For instance, in the event that
the patient is not able to meet the inhalation time goal, the
pre-set inhalation time may be decreased. Alternatively, if the
patient has excess capacity, the pre-set inhalation time period may
be increased. Although a variety of different methods may be
employed to determine the patient's performance, one method of
determining the patient's performance is based on how quickly the
patient ceases inhalation after the patient is signaled to stop
inhalation. In another embodiment, the detected breathing pattern
may be used to determine the time of inhalation to set a pre-set
inhalation time in the memory. In this embodiment, aerosol is
generated during a portion of the inhalation of the patient. As the
user's breathing pattern changes, the pre-set inhalation time may
be adjusted.
While preferred embodiments of the invention have been described
and illustrated above, it should be understood that these are
exemplary of the invention and are not to be considered as
limiting. Additions, deletions, substitutions, and other
modifications can be made without departing from the spirit or
scope of the present invention. Accordingly, the invention is not
to be considered as limited by the foregoing description but is
only limited by the scope of the appended claims.
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